Piston blade



E. WILSON l PISTON BLADE Filed Deo, 26,

IIL

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pumps r underside of the ldatented Aug. 17, 1926. I.

UNITED As''r'aras rse-e135 PATENT DFFICE.

EDWARD wILsoN, or er. Louis; Missoula; Assrenova 'ro `na'rioivnrn ruler AND colit- Pna'sson COMPANY, or sT. Louis; Mr'ss'o'Rr, A Conroe-Arron or DELAWARE.

rrs'ion BLADE.

My invention relates to improvements in piston blades, and has tor its primary obliect a piston blade which is designed for use in rotary compressors or rotary vacuum i and is constructed witha roclring shoe which is designed for constant Contact with the interior ot the cylinder in which the rotor carrying the blade rotates.

Av further object is to construct a piston blade of two separate unattached'membersy which carry on their outer edge .a` rocking shoe, the shoe adapted to rock during. the movement or sweep of the piston blade through a cylinder andtby so rocking to maintain at all times a'relatively wide surface in contact with the interior of the cylinder. Y y A A still further object is to construct a pistony blade having shaped shoe which is carried bytwo compleinentary ilat members, these members b ing capable ofindependent. lateral movement so that the upper edges of the member will always be in contact with the shoulders or head of the shoe thereby maintaining an airtight connection between the shoe and the individual members of the blade.

In the drawings: Y

Fig. 1 is a face view of my improved blade with the shoe in position;

Fig. 2 is a vertical section taken on the line 2-2 of Fig. 1;

3 is an end view the shoe removed; y

Fig. 4 is an inside face view of one of the sections; I

Fig. 5 is an end view of the shoe;

Fig. 6 is a fragmental view showing` a portion of the rotor and cylinder with my blade in position and just ready to "com-k of my blade with mence sweeping through the compression chamber; l. l

Fig. 7 isa similar view showing the-position of thel various part-s of the blade when a quarter revolution has been made;

Fig. 3 is a similar view when a half revolution has been completed;

Fig. 9 is a similar view when three-quarters of a revolution has been made; and

Fig. 10 is a view of my blade illustrating the movement of the blade sections and ecking shoe and showing how the air-tight joint is maintained between the shoulders of a substantially .TV

alongy the lower edge Vsimilarly but has lthe center Application inea December ze, 1925. serial No. 77,687.

the shoe and the upper edges of the blade.

1n the construction of my device Iy employ a piston bladecomposed of complementary Aplates 11 and 12. rlhe plate 11 is provided with ribs 13 and 14 and the plate 12 with ribs 15 and 16. I1`hese ribsare designed to abut as illustrated in Figs. 2 and 3 thus forming a pressure space or pocket 17. rThe ribs 13 and 16 are adjacent one of the longitudinal edges of the plates while the` ribs 14 and 15 are positioned at some distance below the edges 18 and 19 of the plates 11 and 12 respectivelyT so as to form a channel. or groove channel or groove are preferably tapered as illustrated in Figs. 2 and 3. KVlhe shoe, which is located in this channel or groove, is substantially T shaped having a head 21.

20. vThe walls of this The upper face 22 of this head is curved so j that it will bear snugly against the interior of the compression cylinder. Therefore', the curvature of this face will be Varied withvarious faces of cylinders.

Xtending downwardly and at an angle to the vertical are the longitudinal faces 23, oi which are formed shoulders 24 and 25. Below the shoulders isa extension y26 which has curved longif tudinal walls 27 and 23. These 1walls are curved on .the arc of a circle having as its center a point midway .the width of the shoulder 24 while the wall 27 is curved .of its curve taken ,on the shoulder 25.l These curved walls form a .rolling contact withthe walls ofthe channel or groove so as toeliminate lwear at these points. 'One ot the plates either 11 or 12 hassecuredth'ereto resilient or spring members 29,'the tree ends or which contact with the opposite plate. The purpose of this is to have the plates spread apart so that they will iit snugly against the walls of the piston blade pocket which is .formed in the rotor.

My p'ston blade may be operated either mechanically or by centrifugal `force, and by operation is meant the holding ot the shoe against the interior face of the compression cylinder and the sections of the blade against the shoulders 25 and 24. It will be noted trom Figs. 7 and 9 that in order to maintain a tight joint and a full contact between the shoe and the interior of the cylinder, the shoe must reak and in so doing one of the shoulders will have a tendency to raise or draw away from the upper edge of one of the plates. Then this occurs centrifugal force will move that section of the blade outward and maintain a tight joint. It is, of course, to be understood that my device is used in con'ipressors Where the rotor is mounted eccentrically to the compression cylinder. This is clearly illustrated in Figs, 6, 7, 8 and 9 in which also a .mechanical means for moving and maintaining the piston against the cylinder head is shoivn by dotted lines.

During the operation of my device, there Will alvvays be more lor less oil fed to the compression chamber, which will be distributed over the piston and this yoil gets in betiveen the shoulders 25 and 24- and the edgeslS and l5) ivill form an oil seal and assist in making the joint air-tight. The oil will also get on the faces of the ribs and the free ends of the resilient members 29 thus permitting the plates to slide on each other and assume the position shoivn in l0.

While I have shown my device as employing a leaf spring, it is obvious that other means may be used, which have a normal tendency to force the plates apart or these parts may be omitted entirely there will always be sufficient amount of gas pressure between the plates entering through the ports 30 to hold them apart when the device is in operation. lhese ports may be either openings drilled throngl'i the ribs or may be made by cutting notches of any desired shape in the vertical edges of the ribs. It is also an essential feature of my device that the length of the shoe and the length of the plates be exactly the same so that there can be no leakage past the piston from the compression chamber into the suction chamber.

Having fully described my invention, wiat I claim is l. A piston blade composed of complementary sections slidably arranged against eachother so as to form a groove in the outer edge of said blade, and a shoe of the same length as the blade located in said groove, said shoe capable of being rocked by the relative outward movement of said sections.

2. A piston blade composed of complementary sections slidably arranged against each other s o as to form a channel in the outer edge of said blade, al shoe of the same length as the blade located in said channel, said shoe capable of being rocked by the relative outward movement of said sections, and means interposed between said sections for normally forcing them apart.

3. A piston blade composed of complementary sections slidably arranged against each other so as to form a groove in the outer edge of said plate, a shoe located in said groove, said shoe capable of being rocked by the relative outward movement of said sections, and a spring interposed between said sections.

4L. A piston blade composed of tivo sections arranged face to face and capable of being moved relative to each other, a groove formed in the outer edge of said blade, a

shoe mounted in said groove, shoulders formed on the opposite face of said shoe intermediate its edges and adapted to engage with the outer edges of the sections whereby the shoe may be rocked by the relative movement of the sections and an air-tight connection is formed and maintained betiveen said shoulders and the edges of the sections.

5. A piston blade composed of complementary sections provided With pockets on their inner surfaces, said sections slidably arranged against each other so as to form a groove in the outer edge of said blade, a shoe of the same length as the blade located in said groove and adapted to rock therein by the relative movement of the sections, and a leaf spring mounted in one of said poel-:ets and projecting into the other pocket for normally forcing the sections apart.

6. A piston blade composed of sections provided with ribs on their inner faces and slidably arranged against each other so as to form a groove in the outer edge of said blade, each of the sections being provided with pockets on the inside face between the ribs, said blade being provided ivith a groove or recess in its outer edge, and a shoe of the same length as the blade located in said groove and capable of being rocked by the relative outward movement of said sections.

7. A piston blade composed of complementary sections provided vfith a pressure pocket on the inside faces thereof, said sections being slidably arranged and provided with a channel in their outer edges, a shoe of the same length as the blade located in said channel, said shoe capable of being rocked by the relative outward movement of said sections.

In testimony whereof l have aiiixed my signature.

EDWARD ivnesoN. 

